What does the kind of sword a character uses have to do with being unique?
I mean, it's something to notice aesthetically, but it doesn't sound like it has to do with gameplay when gameplay is what makes a character unique first and foremost.
This is exactly why Robin stands out so much as a sword-user: It's not that he has a unique sword--I mean, it's literally a dinky bronze sword with the occasional Falchion-dipped-in-Pikachu-juice substituting in on occasion--but rather the system in which durability applies to his weapons and causes the need for strategic use of his moves. Playing him feels different than playing as another character. The kinaesthetics that come out of his Levin Sword's Glass Cannon-like fragility are a result of his unique gameplay. Likewise, the sturdiness of Link's Master Sword as a back-up to his heavy use of projectiles, or the focal point of power that exists within Marth's Falchion's tip, or the swiftness of Meta Knight's Galaxia that feels nothing Ike's Ragnell in its heavy, slow approaches. It's not about the swords themselves, but rather what they do in gameplay. Heck, all of these guys could be punching instead of using swords, but would be just as unique from one another if they retained the same attributes in terms of hitbox sizes, power, speed and the works.
What I'm more interested in is not the idea of Takamaru using a katana, but rather, how said katana is used. If he's just a rushdown character that focuses on building up tiny hits like Meta Knight and Sheik, that honestly doesn't sound enticing as another character to add, imo. What would he feel like to play as?